Re: [HACKERS] Re: Improve OR conditions on joined columns (commonstar schema problem) - Mailing list pgsql-hackers

From Peter Geoghegan
Subject Re: [HACKERS] Re: Improve OR conditions on joined columns (commonstar schema problem)
Date
Msg-id CAH2-WzmWSDO3KTMQqMVH6emCz-Y0G7C_WZwLF40pocfj7SBxFw@mail.gmail.com
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In response to Re: [HACKERS] Re: Improve OR conditions on joined columns (commonstar schema problem)  (Peter Geoghegan <pg@bowt.ie>)
List pgsql-hackers
On Thu, Aug 23, 2018 at 5:20 PM, Peter Geoghegan <pg@bowt.ie> wrote:
> This patch adds an enhancement that is an example of a broader class
> of optimizer enhancement primarily aimed at making star-schema queries
> have more efficient plans, by arranging to use several independent
> nested loop joins based on a common pattern. Each nestloop join has
> one particular dimension table on the outer side, and the fact table
> on the inner side.

Correction: I meant that for each join, the outer side is a scan of
some particular fact table index, while the inner side probes some
particular dimension table's primary key, and evaluates the
dimension's qual.

-- 
Peter Geoghegan


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